From 827843bbbdb5a27019d7d679f371a3a69053c762 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 12 Jun 2013 10:12:50 +0200
Subject: Complete the lapack interface to make it complete enough for
 suitesparse QR.

---
 lapack/dladiv.f | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 lapack/dladiv.f

(limited to 'lapack/dladiv.f')

diff --git a/lapack/dladiv.f b/lapack/dladiv.f
new file mode 100644
index 000000000..090a90654
--- /dev/null
+++ b/lapack/dladiv.f
@@ -0,0 +1,128 @@
+*> \brief \b DLADIV
+*
+*  =========== DOCUMENTATION ===========
+*
+* Online html documentation available at 
+*            http://www.netlib.org/lapack/explore-html/ 
+*
+*> \htmlonly
+*> Download DLADIV + dependencies 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dladiv.f"> 
+*> [TGZ]</a> 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dladiv.f"> 
+*> [ZIP]</a> 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dladiv.f"> 
+*> [TXT]</a>
+*> \endhtmlonly 
+*
+*  Definition:
+*  ===========
+*
+*       SUBROUTINE DLADIV( A, B, C, D, P, Q )
+* 
+*       .. Scalar Arguments ..
+*       DOUBLE PRECISION   A, B, C, D, P, Q
+*       ..
+*  
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*> DLADIV performs complex division in  real arithmetic
+*>
+*>                       a + i*b
+*>            p + i*q = ---------
+*>                       c + i*d
+*>
+*> The algorithm is due to Robert L. Smith and can be found
+*> in D. Knuth, The art of Computer Programming, Vol.2, p.195
+*> \endverbatim
+*
+*  Arguments:
+*  ==========
+*
+*> \param[in] A
+*> \verbatim
+*>          A is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] B
+*> \verbatim
+*>          B is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] C
+*> \verbatim
+*>          C is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] D
+*> \verbatim
+*>          D is DOUBLE PRECISION
+*>          The scalars a, b, c, and d in the above expression.
+*> \endverbatim
+*>
+*> \param[out] P
+*> \verbatim
+*>          P is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[out] Q
+*> \verbatim
+*>          Q is DOUBLE PRECISION
+*>          The scalars p and q in the above expression.
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee 
+*> \author Univ. of California Berkeley 
+*> \author Univ. of Colorado Denver 
+*> \author NAG Ltd. 
+*
+*> \date November 2011
+*
+*> \ingroup auxOTHERauxiliary
+*
+*  =====================================================================
+      SUBROUTINE DLADIV( A, B, C, D, P, Q )
+*
+*  -- LAPACK auxiliary routine (version 3.4.0) --
+*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
+*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+*     November 2011
+*
+*     .. Scalar Arguments ..
+      DOUBLE PRECISION   A, B, C, D, P, Q
+*     ..
+*
+*  =====================================================================
+*
+*     .. Local Scalars ..
+      DOUBLE PRECISION   E, F
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          ABS
+*     ..
+*     .. Executable Statements ..
+*
+      IF( ABS( D ).LT.ABS( C ) ) THEN
+         E = D / C
+         F = C + D*E
+         P = ( A+B*E ) / F
+         Q = ( B-A*E ) / F
+      ELSE
+         E = C / D
+         F = D + C*E
+         P = ( B+A*E ) / F
+         Q = ( -A+B*E ) / F
+      END IF
+*
+      RETURN
+*
+*     End of DLADIV
+*
+      END
-- 
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